Just your usual reminder I'm going to be peppering you with questions about everything XD (and then you'll get mad at me because I might use far future tech as an excuse for artistic license to do terrible things)
...the holding the wrist with the off-hand thing is something I never understood o_O
I've drawn one handed sideways gun before XD It was purely for aesthetics though, at the time I wasn't sure if a gun could be shot one handed but I did know they probably shouldn't be sideways (and that was purely because I've handled an unloaded gun before and the balance is super weird when it's sideways I don't know why anyone would deliberately try and shoot it like that).
Feel free to question away for sure. I also just uploaded one about some reloading equipment.
Holding the wrist and not the gun will provide zero stability. It's the gun, the recoil, that needs management, not the wrist. Still, Elizabeth Hurley was wearing a nicely-tight jump-suit at the time so it worked. Lol.
The sideways gun thing is dumb Literally no reason for it. It even looks stupid.
Although, when I am shooting one handed I always cant the gan inwards, if my right hand then it's tilted slightly left and if the gun is in my left then I tilt it slightly right. Not much mind you, just a little. It provided a little extra stability. I also change my whole stance to make sure more of my shoulder is behind the gun to provide some recoil management. It's all designed to be able to shoot accurately and back up faster with subsequent shots.
Anyway, ask anything, I don't mind.